U.S. patent application number 11/660452 was filed with the patent office on 2007-12-20 for mould for the injection moulding of a plastic piece and moulding method.
Invention is credited to Alain Di Rienzo, Annabelle Roy-Martinache.
Application Number | 20070292637 11/660452 |
Document ID | / |
Family ID | 34949356 |
Filed Date | 2007-12-20 |
United States Patent
Application |
20070292637 |
Kind Code |
A1 |
Roy-Martinache; Annabelle ;
et al. |
December 20, 2007 |
Mould For The Injection Moulding Of A Plastic Piece And Moulding
Method
Abstract
A mould is provided for the injection molding of a plastic piece
that includes at least two adjacent parts of two compatible plastic
materials, assembled to one another by welding or gluing, of
different types and/or colors. The mould includes a mould cavity
defined by at least two non-planar walls and at least one
retractable wall movable between extended and retracted positions,
dividing the mould cavity into at least two compartments supplied
separately with plastic. When extended, a non-linear edge of the
retractable wall cooperates with a wall of the mould cavity in a
play-free manner. The retractable wall includes panels joined in at
least the extended or retracted position, movable in relation to
one another so they can modify the shape of the non-linear edge of
the retractable wall to adapt it to the shape of a second wall of
the cavity in the retracted position.
Inventors: |
Roy-Martinache; Annabelle;
(Cergy Pontoise, FR) ; Di Rienzo; Alain; (Asnieres
Sur Oise, FR) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Family ID: |
34949356 |
Appl. No.: |
11/660452 |
Filed: |
August 18, 2005 |
PCT Filed: |
August 18, 2005 |
PCT NO: |
PCT/FR05/02112 |
371 Date: |
April 16, 2007 |
Current U.S.
Class: |
428/31 ; 264/299;
425/451.7 |
Current CPC
Class: |
B29C 45/1639
20130101 |
Class at
Publication: |
428/031 ;
264/299; 425/451.7 |
International
Class: |
B29C 45/16 20060101
B29C045/16; B60R 13/00 20060101 B60R013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 18, 2004 |
FR |
0408963 |
Claims
1. A mould for injection moulding a part of plastics material (30)
comprising at least two adjacent parts (15, 16) comprising two
compatible plastics materials assembled together by welding or
adhesive bonding, of different kinds and/or colours, the mould (1)
comprising a mould cavity (2) bounded by at least two non-planar
walls (3, 4) and at least one retractable wall (5) which can move
between an extended position and a retracted position through which
the mould cavity (2) can be divided into at least two compartments
(6, 7) which can be separately fed with plastics material,
characterised in that in the extended position the retractable wall
(5) has a non-linear edge (13) acting together with a wall (4) of
the mould cavity without any play, and in which the retractable
wall comprises a plurality of panels (10, 11, 12) which are
contiguous in at least the extended position or the retracted
position, the said panels (10, 11, 12) being able to move in
relation to each other in such a way as to alter the linear edge of
the retractable wall to adjust it to the shape of a second wall (3)
of the mould cavity (2) when in the retracted position.
2. A mould according to claim 1, characterised in that the edge
(13) of the retractable wall (5) comprises at least three
non-co-linear portions (20, 21, 22) and in which the retractable
wall comprises at least one panel (10, 11) which can be moved
between the extended position and the retracted position by two
successive movements in two different directions.
3. A mould according to claim 2, characterised in that the edge of
the retractable wall (13) comprises a central portion (20) in the
form of a segment which is prolonged at its two extremities by
terminal arcs (21, 22) which are not co-linear with the central
segment, and in that in the extended position the retractable wall
comprises two lateral panels (10, 11) separated by a retractable
central panel (12), the lateral panels (10, 11) being capable of
moving in two perpendicular directions so as to be moved into a
retracted position by two successive movements in two different
directions.
4. A mould according to claim 1, characterised in that it comprises
a plurality of retractable walls.
5. A process for manufacturing a part of plastics material (30)
comprising at least two adjacent parts (15, 16) comprising plastics
material of different kinds and/or colours by moulding in a mould
(1) according to claim 1, characterised in that: at least one
retractable wall (5) of the mould (1) is placed in the extended
position in such a way as to bound at least two adjacent mould
compartments (6, 7), at least one first compartment (6) is filled
with a first plastics material, and allowed to cool, as a result of
successive movements of the panels (10, 11, 12) of at least one
retractable wall (5) the said wall is retracted in order to move it
into a retracted position, at least one second compartment (7)
adjacent to the first compartment (6) is filled with a second
plastics material and allowed to cool, and then the part is turned
out.
6. A process according to claim 5, characterised in that the first
plastics material is allowed to cool partly before the said at
least second compartment is filled with the second plastics
material.
7. A part of plastics material (30) of non-planar shape comprising
at least two adjacent parts (15, 16) comprising plastics materials
of different kinds and/or colours and having a junction zone
bounded by two lines which are not straight when projected onto a
transverse cross-sectional plane, and which are not derived from
each other by translational movement, the said part being obtained
by the process according to claim 5.
8. A part of plastics material according to claim 7, characterised
in that it comprises a component of the interior or exterior trim
of a motor vehicle.
9. A mould according to claim 2, characterised in that it comprises
a plurality of retractable walls.
10. A mould according to claim 3, characterised in that it
comprises a plurality of retractable walls.
11. A process for manufacturing a part of plastics material (30)
comprising at least two adjacent parts (15, 16) comprising plastics
material of different kinds and/or colours by moulding in a mould
(1) according to claim 2, characterised in that: at least one
retractable wall (5) of the mould (1) is placed in the extended
position in such a way as to bound at least two adjacent mould
compartments (6, 7), at least one first compartment (6) is filled
with a first plastics material, and allowed to cool, as a result of
successive movements of the panels (10, 11, 12) of at least one
retractable wall (5) the said wall is retracted in order to move it
into a retracted position, at least one second compartment (7)
adjacent to the first compartment (6) is filled with a second
plastics material and allowed to cool, and then the part is turned
out.
12. A process for manufacturing a part of plastics material (30)
comprising at least two adjacent parts (15, 16) comprising plastics
material of different kinds and/or colours by moulding in a mould
(1) according to claim 3, characterised in that: at least one
retractable wall (5) of the mould (1) is placed in the extended
position in such a way as to bound at least two adjacent mould
compartments (6, 7), at least one first compartment (6) is filled
with a first plastics material, and allowed to cool, as a result of
successive movements of the panels (10, 11, 12) of at least one
retractable wall (5) the said wall is retracted in order to move it
into a retracted position, at least one second compartment (7)
adjacent to the first compartment (6) is filled with a second
plastics material and allowed to cool, and then the part is turned
out.
13. A process for manufacturing a part of plastics material (30)
comprising at least two adjacent parts (15, 16) comprising plastics
material of different kinds and/or colours by moulding in a mould
(1) according to claim 4, characterised in that: at least one
retractable wall (5) of the mould (1) is placed in the extended
position in such a way as to bound at least two adjacent mould
compartments (6, 7), at least one first compartment (6) is filled
with a first plastics material, and allowed to cool, as a result of
successive movements of the panels (10, 11, 12) of at least one
retractable wall (5) the said wall is retracted in order to move it
into a retracted position, at least one second compartment (7)
adjacent to the first compartment (6) is filled with a second
plastics material and allowed to cool, and then the part is turned
out.
14. A part of plastics material (30) of non-planar shape comprising
at least two adjacent parts (15, 16) comprising plastics materials
of different kinds and/or colours and having a junction zone
bounded by two lines which are not straight when projected onto a
transverse cross-sectional plane, and which are not derived from
each other by translational movement, the said part being obtained
by the process according to claim 6.
Description
[0001] This invention relates to the injection moulding of a
plastics part comprising at least two adjacent parts comprising two
plastics materials of different kinds and/or colours.
[0002] Some plastics parts, and in particular parts for the
interior trim of motor vehicles, comprise several adjacent parts of
different colours or appearances. These parts are obtained for
example by injection moulding parts in a mould in which surface
skins of different colours or textures have already been placed.
Such a process has the disadvantage that it requires several
operations and in particular the preparation of surface skins
corresponding to parts of different kinds and/or colours.
[0003] In order to manufacture such parts moulds in which the mould
cavity can be subdivided into several parts through the use of a
moving wall or moving blade which can be retracted may also be
used. In such moulds the moving wall is first located in an
extended position so that it divides the mould cavity into two
parts, and a first plastics material is injected into a first part
of the mould cavity. After the injected plastics material has
solidified the moving wall is moved into a retracted position which
places the second part of the mould cavity in communication with
the part which has already been filled with plastics material by
injection. The second plastics material is then injected into the
second part of the mould cavity. This second plastics material
comes into contact with the already solidified plastics material
and adheres to this first plastics material through welding. This
technique has a disadvantage in that it is only suitable for parts
which have flat walls. In fact, in order to ensure a satisfactory
seal for the two parts of the mould cavity bounded by the moving
wall it is necessary to use a moving wall which has one edge in
close contact with a surface of the mould cavity in the extended
position and which perfectly matches the second surface of the
mould cavity in the retracted position. This arrangement in
particular requires that the mould cavity should be planar, at
least in the area of contact with the edge of the moving wall. This
constraint constitutes a limitation and a disadvantage because it
is often desirable to manufacture parts of plastics material
comprising several adjacent parts of different kinds and/or colours
having non-planar surfaces.
[0004] The object of this invention is to overcome this
disadvantage by providing means for injection moulding a part of
plastics material comprising at least two adjacent parts made of
two plastics materials of different kinds and/or colours in order
to manufacture a part having non-planar walls.
[0005] For this purpose the invention relates to a mould for
injection moulding a part of plastics material comprising at least
two adjacent parts constituting two plastics materials of different
kinds and/or colours which are compatible and assembled together by
welding or adhesive bonding, the mould comprising a mould cavity
bounded by at least two non-planar walls and at least one moving
wall which can be retracted from an extended position to a
retracted position, through which the mould cavity can be divided
into at least two compartments which can be fed with plastics
material separately. In the extended position the retractable wall
has a non-linear edge which acts together with a wall of the mould
cavity without any play, and the retractable wall comprises a
plurality of panels which are contiguous in at least the extended
position or the retracted position, the said panels being able to
move with respect to each other in such a way that they can change
the shape of the non-linear edge of the retractable wall in order
to adjust it to the shape of a second cavity wall in the retracted
position.
[0006] Preferably the retractable wall comprises at least three
non-co-linear portions and the retractable wall comprises at least
one panel which can be moved between the extended position and the
retracted position in two successive movements in two different
directions.
[0007] The edge of the retractable wall comprises for example a
central portion in the form of a segment which is extended at its
two extremities by terminal arcs which are not co-linear with the
central segment, and in the extended position the retractable wall
has two lateral panels separated by a central retractable panel,
the lateral panels being able to move in two perpendicular
directions in such a way that they can be moved into a retracted
position by two successive movements in two different
directions.
[0008] The mould may comprise a plurality of retractable walls.
[0009] The invention also relates to a process for manufacturing a
part of plastics material comprising at least two adjacent parts
formed of plastics materials of different kinds and/or colours by
moulding in a mould according to the invention. According to the
invention: [0010] at least one retractable wall of the mould can be
placed in an extended position in such a way as to bound at least
two adjacent moulding compartments, [0011] at least one first
compartment can be filled with a first plastics material and
allowed to cool, [0012] through successive movements of the panels
of at least one retractable wall the said wall can be retracted in
order to move it into a retracted position, [0013] at least one
second compartment adjacent to the said first compartment can be
filled with a second plastics material, allowed to cool and turned
out.
[0014] Finally the invention relates to a part of plastics material
of non-planar shape comprising at least two adjacent parts
comprising plastics materials of different kinds and/or colours and
having a junction zone bounded by two lines which are not straight
in projection in a transverse cross-sectional plane and which are
not derived from each other by translational movement, the said
part being obtained by the process according to the invention.
[0015] The part of plastics material comprises for example an
element of the interior trim of a motor vehicle.
[0016] Other advantages and characteristics of the present
invention will become clear from the following detailed description
which is given with reference to the appended drawings which are
provided purely by way of non-limiting example and in which:
[0017] FIGS. 1A, B, C, D are perspective view of a mould for the
injection moulding of a part of plastics material comprising at
least two adjacent parts of different kinds and/or colours, the
mould comprising a retractable wall comprising a plurality of
movable panels; the retractable wall is illustrated in different
positions.
[0018] FIGS. 2A, 2B, 2C and 2D are cross-sectional views of the
mould in FIGS. 1A, B, C and D cut by a plane passing through the
movable wall of the mould,
[0019] FIG. 3 is a perspective view of a part obtained by moulding
using the mould illustrated in FIGS. 1A, B, C and D.
[0020] The mould referred to in general by 1 in FIG. 1A comprises a
mould cavity 2 bounded by a non-planar bottom wall 3 and a
non-planar top wall 4 which are generally parallel to each
other.
[0021] Mould cavity 2 is divided by a retractable wall 5 into a
first mould compartment 6 and a second mould compartment 7 each fed
through an injection hole, 8 for compartment 6 and 9 for mould
compartment 7.
[0022] In the extended position as illustrated in FIG. 1A or FIG.
2A retractable wall 5 comprises three adjacent panels: 2 extremity
panels 10 and 11 separated by a central panel 12. The three
adjacent panels 10, 11 and 12 define a top edge 13 which comes into
contact with top wall 4 of the mould. In this arrangement the two
mould compartments 6 and 7 are completely separated. The plastics
material can then be injected through a first injection hole 8, for
example, as illustrated by the arrow shown in FIG. 1A, to form a
first part 15 of a part of plastics material.
[0023] As illustrated in FIG. 1B or FIG. 2B, central panel 12 of
retractable wall 15 can be moved downwards as indicated by the
vertical arrow, which releases a space between lateral panels 10
and 11 and makes it possible for them to move laterally in the
direction of the two horizontal arrows illustrated in FIG. 1B or 2B
in order to approach each other.
[0024] Central moving panel 12 has a top part 12' of a width equal
to twice the thickness of mould cavity 2 in its lateral extremity
parts, although once central panel 12 is retracted and lateral
panels 10 and 11 are brought together to come into contact with
each other in the central part, set of panels 10 and 11 can be
moved vertically as shown in FIGS. 1C and 2C by a movement in the
direction of the two vertical arrows. Following this movement, and
as shown in FIG. 1D or 2D, lateral panels 10 and 11 then form a
retracted wall whose top edge 14 exactly matches the shape of
non-planar bottom wall 3 of mould cavity 2. In this arrangement
which corresponds to the retracted position of retractable wall 5,
upper edge 14 of the retractable wall in the retracted position
completes non-planar bottom wall 3 of the mould.
[0025] When the retractable wall is retracted second mould
compartment 7 is bounded by the two non-planar walls 3 and 4 of the
mould, top edge 14 of the retractable wall in the retracted
position and by the first part 15 of the part present in first
compartment 6 into which plastics material has already been
injected. A second plastics material of a different colour or kind
from the first plastics material can then be injected through
second injection hole 9 to form the second part of the part of
plastics material comprising two parts of different colours or
kinds. This second part 16 is welded onto first part 15 of the
part.
[0026] In order to manufacture a part 30 of plastics material
comprising two parts of different kinds or colours having
non-planar surfaces as illustrated in FIG. 3, a start is made by
separating mould cavity 2 into two mould compartments 6 and 7 by
positioning retractable wall 5 in the extended position. In this
extended position retractable wall 5 comprises three adjacent
panels and its top edge 13 is in contact with non-planar top wall 4
of mould cavity 2. A first plastics material is then injected into
first compartment 6 through first injection hole 8, and then the
plastics material which has been injected is allowed to cool or
solidify to form the first part 15 of the part of plastics
material. Wall 5 is then retracted by moving it into a retracted
position in which its top edge 14 completes non-planar bottom wall
3 of wall cavity 2. In order to do this the shape of the top edge
of the retractable wall is changed, starting with retracting
central panel 12, as a result of which the two lateral panels 10
and 11 can approach each other through a first horizontal movement,
and then moving these two panels downwards in a second vertical
movement. Through these operations a top edge 14 of the retractable
wall is obtained which is both continuous and perfectly matches
non-planar bottom wall 3 of mould cavity 2. In this arrangement
second mould cavity 7 is bounded at one of these extremities by the
first part 15 of the part of plastics material. A second plastics
material which is selected in such a way as to be compatible with
and weldable to the plastics material of the first part, but which
may have different properties because special additives have been
added to it, or which may be of a different colour, or which may be
both of a different colour and have different additives, is then
injected through second injection hole 9. This plastics material
injected into the second compartment forms the second part 16 of
the part of plastics material. Once this second plastics material
has been completely injected into second mould compartment 7 the
whole is allowed to cool, and then the part is turned out and a
part comprising two adjacent parts of plastics materials of
different colours and/or kinds is obtained.
[0027] Advantageously the cooling or solidification of the first
injected plastics material is partial so that the first material
remains essentially sufficiently ductile, so that when the second
material is injected the two materials penetrate each other to a
greater or lesser extent.
[0028] With an increasing level of cooling, welding, that is
interpenetration of the two materials or bonding, that is to say
surface adhesion between the two materials through surface fusion,
takes place.
[0029] Another parameter bringing about welding or adhesion results
from the materials used and their ductilities at the temperatures
in question. By way of example PP is more fluid than ABS and at an
equivalent temperature PP forms a weld whereas ABS forms an
adhesive bond.
[0030] It will be noted that walls 3 and 4 of the first and second
mould compartments may for example have different surface
appearances in order to impart different polished or grained
appearances to the two parts of the plastics part.
[0031] It will also be noted that top edge 13 of retractable wall 5
has three non-co-linear portions when that wall is in the extended
position, these being a central segment 20 and two lateral terminal
arcs 21 and 22 extending in directions perpendicular to central
segment 20. Likewise bottom edge 14 of retractable wall 5 has three
non-co-linear portions when in the retracted position, these being
a central segment 20' and two lateral terminal arcs 21' and 22'
which are not co-linear with central segment 20'. It will be noted
in particular that segments 20 and 20' are parallel to each other,
but segment 20' is shorter than segment 20, and that terminal arcs
21' and 22' can be derived from terminal arcs 21 and 22 by
translational movements. As a result of these arrangements mould
cavity 2 can be perfectly separated by a retractable wall 5 of
variable geometry as described.
[0032] The mould which has just been described comprises two
adjacent mould compartments capable of manufacturing a part
comprising two adjacent parts of different kinds and/or colours.
But it is obvious that a mould comprising more than two adjacent
mould compartments separated one from the next by retractable walls
can be envisaged. Thus parts of plastics material comprising more
than two adjacent parts of different kinds and/or colours, and for
example three adjacent parts, or four or even more parts, may thus
be manufactured.
[0033] Likewise the shape of part 30 as illustrated in FIG. 3 is
that of a part comprising a wall comprising a flat panel
terminating in rounded lateral edges extending perpendicularly to
the line joining the two parts of different kinds or colours.
However it is possible to manufacture parts having different shapes
and comprising for example several adjacent planar panels each
orientated in a particular direction. Such a part comprising
several planar panels which are not parallel to each other is a
non-planar part which in order to be moulded in a mould comprising
a mould cavity which can be separated into several compartments by
at least one retractable wall also requires retractable walls
comprising several panels moving with respect to each other which
can be moved in such a way as to form walls having a first shape in
an extended position and a different shape in a retracted position.
Those skilled in the art will be able to define retractable walls
comprising appropriate panels in order to bring about this
necessary geometrical evolution between the extended positions and
the retracted positions on an individual basis.
[0034] The process which has just been described can be used to
manufacture a great variety of parts of plastics material
comprising several adjacent parts comprising plastics materials
which are compatible and assembled together by welding or adhesive
bonding, but of different kinds and/or colours. These parts are for
example parts of motor vehicle dashboards, or parts of the interior
trim of motor vehicle doors, or any other interior or exterior
motor vehicle parts of plastics material.
[0035] The process and the mould which have just been described are
more particularly useful for manufacturing parts comprising at
least two parts of different kinds or colours having non-planar
surfaces and in which these two parts furthermore have a junction
area bounded by lines on the top and bottom walls of the part which
are not straight in orthogonal projection onto a transverse
cross-sectional plane (the plane in FIG. 3), and which cannot be
developed one from another through translational movement parallel
to the plane of movement of the contiguous panels of the
retractable wall of the mould. In particular such a non-straight
(or non-linear) junction line may be at least partly curved or form
a broken line in projection.
[0036] The transverse cross-sectional plane is a plane extending
through the thickness of the part, at least partly containing the
junction surface.
[0037] Such a part having a non-straight junction zone is
illustrated in FIG. 3.
[0038] In orthogonal projection onto a plane perpendicular to the
aforementioned transverse cross-sectional plane the junction area
may have any shape provided that it is compatible with the
movements of the retractable wall. Those skilled in the art will be
able to determine these compatibility conditions.
* * * * *